From...

From https://usa.visa.com/dam/VCOM/download/about-visa/visa-rules-public.pdf

Section 5.8.4.2

5.8.4.2 Prohibition against Split Transaction

A Merchant must not split a transaction by using 2 or more Transaction Receipts, except for thefollowing:
l Prepaymentl Individual Airline ticket
l Ancillary Purchase Transaction
l Individual Cruise Line ticket
l Installment Transaction
l A transaction in which part of the amount is paid with a Visa Card and the other part paid withanother Visa Card or other form of payment
l In the Canada Region, US Region: Transaction that includes a Service Feel In the US Region: Individual passenger railway ticket

The nub is, that an Installment Transaction is a special type of transaction that must be agreed to by the CARD ISSUER upon request from the CARD ACQUIRING BANK

Splitit has not mentioned this in the prospectus nor in the "How it Works" section. A payment gateway (which is what SPT is) cannot initiate this without the Acquirer and the Issuer consenting via the Installment Transaction request.

From what I understand, NO AUSTRALIAN ISSUING BANK supports Installment Transactions via the schemes. I also understand that only iSignthis and Adyen support installment transactions, as these are standard function in European markets.

SPT, by splitting that transaction itself (as self described in the prospectus), is quite piossibly (and very likely) running against the card scheme rules, and it risk fines and penalties from the Schemes and regulators.

In Australia, the retail sector card acquiring (banks) are:

• NAB
• WPC
• CBA
• ANZ
• Cuscal (and the credit unions as part of this)
• Adyen
• iSignthis
• First Data

The card issuers are (of which many "brands" such as Qantas are mere marketing programs on one of these - flip your card over to see the issuer)
NABWPCCBAANZCuscal (and the credit unions as part of this)First DataHeritage Bank